3-Methyl-2-sulfanylbenzoic acid → tert-Butyl 6-(8-methyl-4-oxo-4H-1,3-benzothiazin-2-yl)-2-pyridinecarboxylate

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Reaction Steps

tert-Butyl 6-cyano-2-pyridinecarboxylate (3.2 g, 15 mmol) and 3-methylthiosalicylic acid (4.7 g, 28 mmol) were dissolved in pyridine (40 ml), and the mixture was refluxed for 16 hrs. The solvent was evaporated, and the residue was subjected to a silica gel column chromatography. The fractions eluted with hexane-tetrahydrofuran (2:1, v/v) were collected, concentrated and recrystallized from hexane-tetrahydrofuran to give the titled compound (3.1 g, 56%) as pale yellow crystals.

Provenance & Evidence